The invention relates to displays, and more particularly, to a system that provides fail-safe display performance.
Computer-controlled terminals or displays are commonly used as visual interfaces with computers or other processors. Such displays have been shown to be a possible alternative to instrumentation panels for aircraft or complex machinery. Multiple screens and pull-down menus enable the displays to show a wide variety of information on an as-needed basis. It is possible for several dozen digital or analog dials and indicators to be represented by two or three controllable displays.
In some applications such as avionics or machine control it is important that the display be constantly operational. Redundant viewing systems have been proposed in which a back-up display is provided. If the principal display fails, the back-up display is activated and used. Such a redundant system requires about twice the space of a single display due to the inclusion of the back-up display, and may therefore not be feasible in situations where space is at a premium.
It is therefore an object of the invention to provide a display system that ensures that critical information is always displayed, even in the event of a failure of one of the components of the system.
It is another object of the invention to provide a failsafe display system that minimizes the number of redundant components included therein.
A feature of the invention is a display system having a plurality of projection channels that cooperate to create a substantially tiled image on a display screen, wherein the projection channels are adjusted to optimize the size and content of the displayed image when one of the projection channels becomes inoperative.
An advantage of the invention is that the projection channels compensate for a failed projection channel by adjusting the size, content, and/or proportion of the images projected by the non-failed projection channels.
The invention provides a display system that includes a plurality of projection channels. Each projection channel projects a substantially mutually exclusive portion of an image onto a display area. A controller determines the content and size of each portion that each projection channel projects onto the display area so that the image substantially fills the display area during normal conditions. When one of the projection channels is inoperative, the controller adjusts the portions of the image that are projected by the operative projection channels to optimize the image on the display area.
The invention also provides a display system for projecting an image on a display area, the image having a size and a content. The system includes a first projection channel having a first light modulator configured to modulate light to form a first portion of the image, and a first variably-focusable lens assembly that focuses the first portion of the image for display on the display area. A second projection channel includes a second light modulator configured to modulate light to form a second portion of the image, and a second variably-focusable lens assembly that focuses the second portion of the image for display on the display area. A third projection channel includes a third light modulator configured to modulate light to form a third portion of the image, and a third variably-focusable lens assembly that focuses the third portion of the image for display on the display area. A controller controls the first, second and third lens assembly such that when the first, second and third projection channels are in an operative state, the first portion of the image is displayed on a first section of the display area, the second portion of the image is displayed on a second section of the display area, and the third portion of the image is displayed on a third section of the display area, wherein each of the first, second and third sections of the display area are substantially mutually exclusive and combine to cover substantially all of the display area. The controller is further configured so that, upon failure of one of the projection channels, the controller adjusts the portions of the image to be projected by the remaining operative channels by controlling the modulators and the variably-focusing lens assemblies of the remaining operative projection channels to optimize the size and content of the image.
The invention also includes a method of providing an image to a display screen. According to the method, a plurality of independent projection channels are provided. Each projection channel is configured for modulating light to create a portion of the image and focusing the image on a section of the display screen. The portion of the image that each projection channel is to project is determined. Light is generated for each projection channel. The light in each projection channel is modulated to produce each portion of the image. Each portion of the image is focused on a section of the display screen. An inoperative projection channel is compensated for by modifying the portions of the desired image that each operative projection channel is to project and by re-focusing each portion on the display screen, to thereby optimize the image that is displayed on the display screen.